Some 20 months after the transplant, there is no sign of HIV in his system, according to Gero Hütter, M.D., and colleagues at the Charité-Medical University here.

"We waited every day for a bad reading," Dr. Hütter told reporters this week, some eight months after he first reported the case, in February at the 2008 Conference on Retroviruses and Opportunistic Infections. But, so far, he and colleagues have been unable to find the virus in blood, bone marrow, lymph nodes, intestines, or brain, he said. The bone marrow transplant was not intended as a cure for HIV but as a treatment for an unrelated acute myeloid leukemia, said Dr. Hütter, a hematologist at the hospital.

But, knowing that people whose immune cells have a defect called a CCR5 receptor are protected against the virus, he deliberately sought a donor with such a mutation, the scientist said.

People with the defect make up less than 1 percent of the White population and no Blacks, says Dr. Anthony Faucci, who heads the National Institute of Health's infectious disease division. He also told reporters that the procedure is both too expensive and far too dangerous to be used as a widespread cure.

Also, it may be too early to say the virus is gone, according to Andrew Badley, M.D., of the Mayo Clinic in Rochester, Minn. "A lot more scrutiny from a lot of different biological samples would be required to say it's not present," Dr. Badley told The Associated Press.